Former Chicago Police Supt. Garry McCarthy has formally entered the 2019 race against the mayor who fired him, with a promise to reverse a mass exodus from Chicago triggered by violent crime.

“Unfortunately, Chicago city government has lost our trust, because of failed policies and the endless politics of bluster and bullying,” McCarthy says in a three-minute campaign video released Wednesday night. “I’m running for mayor to change that.”

In the ad, McCarthy slams his ex-boss, calling it “so painful to see that under this mayor, we’re awash in higher taxes, corruption, school closings and violent crime.

“We must return to the values of my parents and their generation: honestly, selflessness, reliability,” McCarthy says in the video.

McCarthy spent 4.5 years arguing that Chicago didn’t need more police officers before being fired for becoming what Mayor Rahm Emanuel called a “distraction” in the unrelenting furor that followed the release of the Laquan McDonald shooting video.

He has doubled down on that argument, saying Emanuel doesn’t need to hire 970 additional police officers at a start-up cost of well over $120 million — and even more overtime as rookie salaries escalate dramatically. The mayor simply needs to stick with the crime-fighting strategy he abandoned as soon as McCarthy was shown the door, the new challenger said.

“You know the [crime statistics] that we had in 2013 and 2014. And that was with the numbers [of officers] that we had. We’ve abandoned the plan. We’ve abandoned the blueprint that’s being used everywhere in the country. And we’re playing politics and expecting to get results,” McCarthy told the Chicago Sun-Times.

“It was breaking up those task forces. Putting the cops in the districts. Holding district commanders accountable. Using technology to ensure we were putting cops in the right places at the right times,” he said. “It was giving them the tools to do their job. And some of the more progressive crime reductions strategies like the gang call-ins, the heat list for individuals most likely to be involved in gun violence as an offender or a victim. It’s about running the police department like a business — not a political organization.”

McCarthy laughed out loud when asked to explain how the Chicago Police Department is being run like a political organization.

“The fallout from Laquan McDonald ended up with a purge in the Police Department starting with me. When I got thrown under the bus, the whole department got thrown under the bus,” McCarthy said.

“Minor disciplinary cases that were in the pipeline when I was superintendent after I was fired resulted in people being forced to retire, because you have to be tough on police because they’re the problem. Police are not the problem in a city where there’s 4,800 people shot each year. Criminals are the problem. But instead of addressing criminals, we’ve emboldened them and hamstrung the police.”

The mayor is certain to make the same argument about McCarthy, who has never held an elected office.

But McCarthy argued Wednesday that the key to solving the city’s financial problems has more to do with stopping the vicious cycle of declining population, school closings and gun violence than it does the $1.4 billion avalanche of tax increases that Emanuel has imposed to stabilize the four city employee pension funds.

“If you want to fix the tax problem in Chicago, stop people from leaving. We’re the only urban center in the country that’s lost population in the last 10 years,” McCarthy said.

“The people we’re losing are taxpayers. As a result, the people left behind have a larger burden. Nothing is going to change in this city until we make it safe. Right now, there is no place in this city that is safe. . . . If we don’t make the city safe, we have to cut services. So what do we do? We close schools on the South and the West Sides. Why? Because of poor attendance.”

McCarthy acknowledged that reversing population losses will take time that the pension funds don’t have.

In the meantime, “There’s other ways to generate money. But I’m not gonna tell you what that is right now because it hasn’t been vetted and there’s a couple of different ways to go to raise revenue for the city,” he said. “Very unique. Very innovative.”

Last week, the Sun-Times ran a headline about McCarthy’s candidacy under the headline “Grudge Match” that stuck in McCarthy’s craw.

He insists that he is running to stop Chicago from “going down the tubes,” as he put it — not because he’s trying to get even with Emanuel for the December 2015 firing.